Design and finite element analysis of a vacuum chuck for weak rigid body parts

Author(s):  
Guanyu Zhou ◽  
Wei Wang ◽  
Lingbao Kong ◽  
Min Xu
2008 ◽  
Vol 130 (8) ◽  
Author(s):  
Pei Xu ◽  
Yu Jingjun ◽  
Zong Guanghua ◽  
Bi Shusheng

A leaf-type isosceles-trapezoidal flexural pivot can be of great practical use for designing compliant mechanisms. The analysis of load-deflection behavior for such a pivot is essential to the study of the mechanisms that are comprised of them. Based on the analysis of a single special loaded leaf segment, a pseudo-rigid-body four-bar model is proposed. The four-bar model is further simplified to a pin-joint model for some simple applications. The accuracy of both models is demonstrated by comparing results to those of nonlinear finite element analysis. At last, the two models are applied to analyze the cartwheel hinge as an example.


Author(s):  
Xu Pei ◽  
Jingjun Yu ◽  
Shusheng Bi ◽  
Guanghua Zong

The Leaf-type Isosceles-Trapezoidal Flexural (LITF) pivot consists of two compliant beams and two rigid-bodies. For a single LITF pivot, the range of motion is small while the center-shift is relatively large. The capability of performance can be improved greatly by the combination of four LITF pivots. Base on the pseudo-rigid-body model (PRBM) of a LITF pivot, a method to construct the Quadri-LITF pivots is presented by regarding a single LITF pivot (or double-LITF pivot) as a the configurable flexure module. Ten types of Q-LITF pivots are synthesized. Compared with the single LIFT pivot, the stroke becomes larger, and stiffness becomes smaller. Four of them have the increased center-shift. The other four have the decreased center-shift. One of the quadruple LITF pivots is selected as the examples to explain the proposed method. The comparison between PRBM and Finite Element Analysis (FEA) result shows the validity and effectiveness of the method.


2018 ◽  
Vol 9 (2) ◽  
pp. 327-336
Author(s):  
Raşit Karakuş ◽  
Engin Tanık

Abstract. Conventional wiper mechanisms that are used in automotive vehicles comprise numerous linkages and joints. In this study, in order to obtain a simpler design, a novel compliant wiper mechanism is introduced. The wiper mechanism is essentially a partially compliant four-bar mechanism. To the best of our knowledge, this is the first compliant wiper mechanism in the literature. The wipers currently labeled “compliant” in the literature possess only a flexible wiper blade frame. However, these are still driven by conventional rigid body mechanisms. After introduction of the fundamental concept, a compliant wiper mechanism is designed for an L7e car. Finite element analysis is carried out for verifying analytical results and fatigue calculations are performed. Finally, a prototype is manufactured, and it is experimentally verified that a compliant wiper mechanism may have an infinite life.


Author(s):  
Issa A. Ramirez ◽  
Craig P. Lusk

The kinematic equations for approximating the deflection of a three-dimensional cantilever beam were developed. The numerical equations were validated with a Finite Element Analysis program. With these equations, a pseudo-rigid-body model (PRBM) for an axisymmetric straight beam was developed. The axisymmetric PRBM consists of a spherical joint connecting two rigid links. The location of the deformed end of the beam is determined by two angles and the characteristic radius factor. The angle of the beam with respect to the vertical axis depends on the direction of the force with respect to the undeformed coordinate system. The Pearson’s correlation coefficient for the Finite Element Analysis model and the numerical integration is 0.952.


2019 ◽  
Vol 9 (19) ◽  
pp. 3966 ◽  
Author(s):  
Nicola Pio Belfiore

This paper presents a new tendon-driven platform with spatial mobility. The system can be obtained as a monolithic structure, and its motion is based on the concept of selective compliance. The latter contributes also to optimizing the use of the material by avoiding parasitic deformations. The presented platform makes use of lumped compliance with three different kinds of elastic joints. An analysis of the platform mobility based on finite element analysis is provided together with an assembly mode analysis of the equivalent pseudo-rigid body mechanism. Surgical operations in laparoscopic environments are the natural fields of applications for this device.


Author(s):  
Paul Montalbano ◽  
Craig Lusk

This paper presents designs for Multistable Shape-Shifting Surfaces (MSSS) by introducing bistability into the Shape-Shifting Surface (SSS). SSSs are defined as surfaces that retain their effectiveness as a physical barrier while undergoing changes in shape. The addition of bistability to the SSS gives the surface multiple distinct positions in which it remains when shifted to, i.e. by designing bistability into a single SSS link, the SSS unit cell can change into multiple shapes, and stabilize within the resulting shape, while maintaining integrity against various forms of external assaults normal to its surface. Planar stable configurations of the unit cell include, expanded, compressed, sheared, half-compressed, and partially-compressed, resulting in the planar shapes of a large square, small square, rhombus, rectangle, and trapezoid respectively. Tiling methods were introduced which gave the ability to produce out-of-plane assemblies using planar MSSS unit cells. Applications for MSSSs include size-changing vehicle beds, expandable laptop screens, deformable walls, and volume-changing rigid-storage containers. Analysis of the MSSS was done using Pseudo-rigid-Body Models (PRBMs) and Finite Element Analysis (FEA) which ensured bistable characteristics before prototypes were fabricated.


Author(s):  
Alden Yellowhorse ◽  
Larry L. Howell

Origami-inspired mechanisms have a variety of potential applications but present many challenges in their design. Problems such as mechanism inflexibility must be considered for any application but may not always be easily resolvable. One option in such a case would be to rely on the inherent flexibility of the origami panels to permit motion. This paper presents a method for increasing the flexibility of a structure and enabling motion in an otherwise immobile origami-inspired mechanism. This method will be derived analytically and then verified through finite-element analysis and experiments.


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